Frictional locking hydraulic clutch.



, c. c. MCH.

YFBICTIONM LOCKNG HYDRAULIC CLUTCH.

MPLICATIOH` FILED MAR. 3, 1913.

maimed Apnzo, w15.

rTS-SHEET 3 SEP C. C. RICH.

FRICTIONAL LOCKING HYDRAULIC CLUTCH.

3 SHEETS-SHEET 2.

C. C. RICH. FRICTLONAL LOCKING HYDRAULIC CLUTCH.

APPLICATION FILED MAR-3|1913.

Patented Apr. 20, 1915.

in@ @i #i 3 SHEETS-SHEET 8.

QBABLES CLYTQN RICH, (2F MGUNT VEBNGN, NEW EGM;

FRICTQNiL LOCKNG ELDRULIC CLUTCH.

Application ied March 3, 1913.

To all whom it mai] concern Be it known that l, CHARLES C. RICH, citizenof the United States, residing at Mount Vernon, in the county oflestchester and State of New York, have invented certain new and usefulImprovements in Frio tional Locking Hydraulic Clutches, of which thefolloivingis :i specification.

My invention relates to clutches and 'pen ticularly to hydrauliccluiches, thai is, clutches wherein n fluid medium is used as o. meansof connecting u driving element with a driven element.

The object of my present invention is the provision of e clutch of thischaracter wherein the driving and driven elem-ents may notI only behydraulically connected, but wherein they may be rictionnlly connectedto secure n practically positive driving engagement 1between che drivenand driving elements of the clutch.

A further object of my invention is io provide n clutch which shallinclude ine-nis for compressing u iiuid medium into the space betweenthe driving :ind the driven elements und which shall also include eplurality of friction disks, certain of the disks being connected to thedriven element` sind certain oi' the disks to the driving:r elemen,

these disks being norma ly held apart, and include hydraulicallyoperated devices for forcing the friction disks ino engngenien with eachoiher to thereby positively connect the driven element. with the drivingf clement.

A. further object o the invention is o provide means whereby :i 'fluidmedium shall first be compressed between the driving and the drivenelements of the clnch sind that the pressure of this viuid medium shelloct to 'force the friction disks into engagement with each other. y

A still further object is to provide in o. clutch of the churncter luststated, u plurality of pistons disposed behind and in operativeongzigemenb with the friction disks io 4provide n duct/lending fromliel'uid coinpression space of the hydraulic portion of the clutch tothe space behind the pistons, ond to provide c. vulve so connected tothe clutch actuating mechanism that einer theV driven elemento" theclutch hes 'been hydraulically., connected to the driving ele,- mentrhereof, ehe compressed iiuid will pass Speccaton of Letters Patent.

,Paifened Apr. 2%), i915.

serial no. reines.

me drawings: Figure .i rical section on he line -l of Fig. 3 of n crutchconstructed in accordance with my invenion; Fig. 2 is e on `che line "J2,-2 of Fig. l; Fig. is on the line of l; Fig.. f Liearicel sectionthrough one i fr elespective vie'vv oi the rotor s o of its blades beingremoved fronivits poclie: Fig. G is n *fragmentary sec-tion o the low rportion oi che fluid rnb-er shown in Fi l', huishowing e, valve 59sliiled inoposition to relieve e" e "oressnie actuating pistons. 'I

Referring'ro 'diese drawings, end incre pnviculzL ly ing vto lig. l. itwill be 'ing element of my clutch designated generally 2, formed ofthree sections ons 3 end forming end seen that nie his casing ff 3, land o, the heads nhuning the section foi septum diviiing ene outercasing 'i chambers -6 onv1 The sectini i Yvides o heed i2,

iis cen'er with hi end protl s lornficd at e projec or 'noss and with o.recess l0 upon the inner face of the head. The boss projects into ncentral recess formed in a wheel and the cas` ement ith Jche iiy wheelby niexins or n plm :jility of pins 1l and by stud bolts operaiivelyengaging the casing and 'che wheel. The iiy wheel A is oi' any ordinaryconstruction, lout is shown' as formed like those iy. wheels tliut areadopted for nitachmcnt to ordinary frictionel clutches commonly i uponautomobiles The sectionfSof the outer casin or driving element is formedwith a hea 12 closing .the end ofthe casing opposite the head 8,this-Ahead 12 being annular'and formed with a central opening for thepassage of an actuating sleeve, which will be later described, and adriven shaft 13. The partition 5 is alsoformed with a central openingforthe passage ofthis shaft 13, and the inner endl of this shaft isconnected in any 'suitable or ordinary manner with a rotor 14.

. By reference. to Fig. 2, it will be seen thatthe Arotor 14 and thedriving element ',or outercasing2 `have the same axis ofrotation,butthat the interior face of the rotor chamber 'Zi-.iseccentric-to the axis of the driven shaftand rotor. It will be also seenfrom this figure that the periphery of the rotor contacts at one point,designated 15, with the inner face of the rotor chamber 7, and uponreference to'Fig. 1 it will be noted that the sides of the rotor fitclosely to the sides'of the rotor chamber.

A While the rotor may be of any construction to accomplish they enddesired, I have t illustrated itzas formed with four radiallyextending.` recesses or pockets 16. These pockets areopen at their ends,and within 'thepockets are disposed. the blades 17 which hafvej'a" widthsubstantially equal to the lwidth-cf the rotor. chamber 7 and are forcedout. against the vinner face of .the rotor chamber, the outer end facesof the blades being beveled. The blades 17 are forced outward. primarilyby means of rods 18 f which-bear against plate 19 and springs 20 whichare disposed within sockets 21 formed in the blades.

. l the direction of the arrow, the chambers or It will be obvious fromFig. 2 that as the outer casing rotates with relation to the rotor, theblades will be reciprocated, and that as one blade moves inward theblade connected therewith -will be moved outward by the movement of therod 18. The springs 20 act to resiliently urge the blades 17 outwardagainst the inner face of the rotor chamber. I do not Wish to be limitedto thc` construction described for the blades, as this may be modifiedin many ways and forms no part of my present invention.

That portion of the Wall of the rotor chamber which is nearest to theaxis of 4rota.- tion of Vthe rotor is nformed with an inlet chamber,designated 22. This chamber 22 is disposed on one side 'of the point 'ofcontact ofthe rotor withthe outer casing.. Assuming that the outercasing 2 is rotating in the direction of the arrow, Fig. 2, and assumingthat the chamber 22 is connected to a lsource .of fluid, then, 'as theouter casing rotates in s `aces defined-by the outer face of the rotor,tte inner face -of'the casing, and the blades '17 will change'theirshape. Thus, the spaces on the inletside of the clutch will graduallybecome llar er, while the spaces on the .out-

let side wil become smaller. As' the spaces' on the-inlet-side, whichspacesare designated a and b in Fig. 2, become larger, they will act tosuck in fluid medium, while the spaces c and d will act to eject thefluid medium, and if no opening is provided through which this fluidmedium may be ejected, then the fluid medium will become clicked Withinthe spaces c and rl and will bind the outer driving element to the inneror driven element, namely, the rotor 14 and the shaft 13. The

wall of the chamber 22 is formed with a lon-y the fiuid medium is beingsucked into the spaces a and Z), the fluid medium will b edrawn infromthe chamber 6 into the vcham- A ber 22, and thence by the port 25into the spaces a, and b. The port 27 is controlled by means of a valve26 connected to the operative mechanism of the rotor, as will be laterstated.

.Disposed in advance of each of the blades 17 and extending into thebodyof the rotor is' a port or passage 28. Each of these ports or passages28 at its inner end communicates with a passage 29. In each of thesepassages is disposed a' sleeve valve 30 which lits the wall of thepassage 29 snugly but is movable outwardly therein. The inner end ofeach passage 28 is. annularly enlarged fas at` 282 to surround thepassage 29 and open there.A into. Each of the valves 30 is extended out#Ward and formed with spacedv outwardly projecting flanges 31, the endsof the valves 30 projecting through a,V head 32 4formed upon a sleeve 33which surrounds the driven shaft 13. This sleeve 33 rotates with thedriven shaft but is longitudinally movable with reference thereto. It isheld in engagement with the driven shaft by means of splines orfeathers34, The flanges 31 er1-- gage theinner and outer faces of the head 32 sothat as the sleeve 33 is shifted, the

valves will be shifted either inward or outward. When the valves 30 areshifted outward, they will uncover the ports 28a of thc passages 28 andpermit the escape of Huid,

.izo

nasales screw-threaded, and this screw-threaded terminal is engaged by ashipper ring 35. This shipper ring 35 has an annular extension 36 whichhas screw-threaded engagement with v'a gland37 sliding upon the drivenshaft. The sleeve 33 passes throughV the central opening of the head 12and through a gland 38, which is mounted within the head 12, packing 39and 40 being disposed between the gland 38 and head and between thegland 37 and the extremity of the sleeve 33.

Surrounding the sleeve 33 within the chamber 6 is a ring 41 within whichthe sleeve 33 is rotatable. This ring is held from longitudinal movementindependent of the sleeve by opposed flanges Llla formed on the sleeve,and the ring lil is provided with outwardly projecting brackets havingpins pivotally engaging Y the valve actuating levers.

The valve 26 is operatively connected with the sleeve 33 b means of alever 42 pivoted to a link 43 which in turn is pivoted to the valve 26.'This lever 42 is pivoted upon a bracket LIL-'l projecting inward fromthe head 12, the other end of this lever being slotted and pivoted tothe bracket i ofthe ring 41. lt will thus beseen that when the sleeve 33is moved outward so as to shift the valves to 'their relief position,the valve 26 will be closed, and that when the valves 30 move inward thevalve 26 will be raised. There is, of course, a neutral position whereinthe valve 26 is slightly open and the valves 30 also slightly open.

In order to provide means for positively and mechanically engaging thedriven element with the driving element, I provide a series of frictionrings which are normally spaced from.. each other butv which are broughtinto engagement with each other after the hydraulic clutch is operated.To this end, the partition 5 is formed with an outwardly projectingannular flange 46,this [lange being formed with notches 47. Disposedinward of this flange 46 are a plurality of frictional rings or annulardisks, one series being designated 48 and the other 49. The annulardisks 48 are provided with 5o projecting teeth which engage in thenotches -7 so that the friction disks 48 will revolve `with the drivingelement. The alternate friction disks 49 are notched upon their inneredgesv and these notchesl are engaged f by pins 5G which extend throughthe central opening of the artition 5 and into the rotor.I so that theseriction disks 49 will rotate with the rotor.

Any .means such as springs 50 .may be'- o used to force the frictiondisks apart when pressure against them is relieved. lVhen the frictiondisks are apart, they will, of course,

rotate independent of each other, but when A they are forced togetherinto frictional conte tact, bothsets of the friction disks will bindchamber 56.

against each other and the driving and driven elements will rotatetogether. For the purpose of forcing these disks into frictionalcontact, I provide a plurality of pistons 51. These pistons are mountedeach in a cylinder 52 formedr in the head 12. r1`he outer ends of thepistons 51 contact with an annular thickened portion 53 formed upon theoutermost ring 48. Y

Extending annularly through the head 12 is a duct 5l which communicateswith the cylinders 52. This duct also communicates by means of anextension 55 with a valve This valve chamber in turn communicates bymeans of a duct 57 with the compression space formed between the outercasing and the rotor on the compression side of the rotor. The valvecasing 56 is cylindrical in form, and the ducts 55 and 57 open into oneside of it by ports v55a and 57a. The opposite side of the wall of thevalve chamber is formed with a port 58 which opens into the chamber 6.

Disposed within the valve chamber 56 is .a cylindrical piston valve 59shown also in Fig. 6. This valve 59 has a circumferential.` groove 60formed in its face, a circumferential groove 61 parallel with the groove60 and a Vcircumferential groove 62, the grooves 61 and 60 being spacedfrom cach otherga' distance equal to the distance between the planes ofthel port 55a and the port 58f The groove 61 is spaced from the groove62a distance eqal to the distance between the plane of port 55a and theplane of port 57a.

When the valve is in the position shown in Fig. 1, the grooves 61 and 62will be re` spectivelyopposite the ports 552L` and` 57a,

and these ports will be operatively connected by means of a longitudinalgroove 63 which intersects the grooves 60, 6l and 62. In this positionof the valve, the groove 60 will be blanked by contact withtheimperferate wall of the valve chamber. lVhen'the valve is shiftedinward, the groove 60 will register with the port 55at and the groove 61will register with the port 58. Communication will thereby beestablished between the duct 55 and the interior of the` chamber 56 andbetween the latter and the chamber 6.- A relief port 64 is also providedin the lower end of the valve chamber 56 and opening into the chamber 6for the purpose of preventing compression between the end of the valveand the end of the chamber and permitting the valve to move freely.

` The valve 59 is operatively connectcdto the sleeve 33 by means ofalever 6'5 which-is pivoted upon a bracket 66'projectin'g from the head12, the inner lend of-this lever 65 being' ivoted to a bracketl 67projecting from t e ring 41.

The eration of my invention is asfol`v lows: 'Ille fluid-medium usedwithin the clutch is' preferablyoil, which is introduced intothelchainber 6 in any convenient or preferredymanner. Tll/'hen'theclutch is at rest and the relief ports are open, -this fluid medium willcollect in the lower portion of the chamber.y 6 below the sleeve lVhcnthe driving element E2 is rotated7 the oil will still remain in theoutermost portio'n -of the case-by reason of the centrifugal action sothat it'niay conveniently enter the port Q7 into the induction side ofthe clutch. it is desired to connect the driven member (namely the rotor14 and the shaft 13) to the drivinor member, the sleeve 33 isishiftedinward. In the neutral'position with the valve 26 and thc valves 30partly open the oil will How through the port 27 into the:

chamber 22 and then escape through pas. sages 28 and 29 and valve 30back into the chamber 6 so that little or no motion willA be imparted tothe rotor. vAs the sleeve is shifted inward, it 4begins to o e'n thevalve 26and close the valves 30. he fluid medium is'theniallowed to besucked into the valves 30 are fully closed, the liuid medium will becomewedged between the rotor and theedriving element on the compression sideofthe clutch and will hydraulically connect the driving and the drivenelements. As the sleeve 33 is moved inward, it will act upon the leverto cause the outward movement of the valve 59 and eventually the,

Orts 61 and 62 ofthis [valve are bi'oiigliti into -thefposition shown inFig. 1. At this pointthe ducts 55 and 57 are connected and asa4consequence the fluid compressed in the chambersc'and ai will flow outand into the iston chambers 52, forcing out the pistons g1' which inAturn will force tlie friction disks "48 and y4:9 into frictioiialengagement with each other. lVlien this has been fully attained the 'driving element is mechanically connected with the driven eleii'ieiit.lVhe-n it is desired to unlateli the' driving and the driveneleinents,the reverse movement takesl lace. l`he sleeve is moved outward. his actsfirst to shift the valve 59 so as to bring kthcgro'ove 60 intocoincidence with the port 55' and the groove 61 into coincidence withthe port 58.; As a consequence, pressurebehindthe pistons 51 is releasedand the istonsare free to move backward and the fictionelements 48 .and49 to separate.` Aiffartl'ier movement of the sleeve y'3 3 graduallywithdrawsgthe valves 30 and gradlVlien ually opens the inner ends of theports 28, thus gradually relieving the compressed fluid medium withinthe chambers c and (Z.

As soon as this compression is fully relieved,

the driving element will rotate independ-- ently of the driven elementand the fluid medium will be carried out'tlirough the pas sages 29 intothe chamber 6. At this time the. valve 26 will be closed preventing theentrance of luidniediurn` into the suction 42 and 65 are nearer theouter ends than theA inner ends of the same so that the inner portlonsof the arms of the levers will have a greater throw than their outerarms` This arrangements() times the operation of the valves 30 and 59that the friction disks will not be moved into engagement until afterthe rotor is moving atifull speed, and, in nnclutching, the pressurebetween the rotor and the casing willnot be relieved until after thepressure upon the friction disks has beenrelieved'. 'i

lVhile I have illustrated what I believe to be the best forni of myinvention, I do not wish to be limited thereto as it is obvious thatmany changes might be made in the details of construction withoutdeparting from -tlievspirit of the invention.

lVhile I have described the frictional locking elements 18 and .49 as inthe form of annular disks, it iste be understood that the shape of theseelements may be varied within a wide range without departing from thespirit of the invent-ion, and that I d0 not wish to be limited to thisparticular manner of fi'ietionally engaging the driving element with thedriven clement as any other means 'for this purpose may be used.Frictional pressure may be secured by means of pistons forced out-wardby the pressure of iluid within the compression space ofthe clutch. Inthe forni illustrated, the variations in speed are secured yby varyingthe pressure of the fluid medium within the comprcsssion space of theclutch, and the friction disks are not designed, as illustrated, to beused for-the purpose of securing variations in speed, the disks beingforced into contact with each other almost instantaneously so as tosecure a mechanical drive'in addition to the hydraulic engagementbetween the driving and the driven elements; In some instances, however,it may be desirable to use the friction elementsas they are ordinarilyused, that is, to permit the driving element to rotate at a differentspeed from the driven los. d

element, the friction elements under these circumstances shifting .withrelation to each other.

In the constructionillustrated, the number and area olf the frictionlookin elements 48 and e9 may be small because o1.F the great pressureavailable, and the fact that the clutching elementsare rotatingat'substantially the same speed at the time of application of pressure,tending to force the friction elements into operative engagement. ltwill l e seen, therefore that as illustrated, these friction elementscrm the means for mechanically connecting the driving element to thedriven element after the driven element is in motion. The reason forusing friction elements inplace of teeth upon the driving and drivenelements, for instance, which would positively engage with each other,is that where the clutch is to be used upon heavy trucks or in likesituations, a certain slippage between the friction elementsis ofadvantage as preventing sudden shock or too great a strain beingsuddenly applied to the driven element.

`While throughout the specifica-tion I have referred to aV compressionor" the fiuid medium, and to a space Within Which the fluid iscompressed, yet the term compression is not strictly accurate. The oilused as the iuid medium is not compressible in itself but is simplysubiected to high pressure which pressure is transmitted to the drivingand the driven elements. t has been found, however, much more convenientto refer to pressure being exerted upon the fluid medium as acompression of the fluid medium, and furthermore this is substantiallycorrect for the reason. that in the churning up of the fluid medium dueto the rotation of the clutch, 'numerous bubbles of air or gas Will findtheir Way into the oil and when the oil kis subjected to extremepressure, the gas contained Within these bubbles Will bev reduced involume and thus the total volume of the iiuid medium will be reduced andin this sense the fluid medium will be compressed. l

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

l. ln a hydraulioclutch, a driving element and a rlriven element, meansfor hydraulically engaging the driving with the driven element, vmeansfor rictionally enfgaging the driving `with the driven element, 4andmeans for securing said rictional engagement after complete hydraulicengagement 4has been secured.

,ln Aat hydraulic clutch, a drivinff elevmeritQa driven element, aplurality ci fricti'onallyi contacting elements, certain of jvhich areoperatively4 connected with the driving element of the clutch, andcertain vothers of which are operatively connected With the drivenelement of the clutch, means for hydraulically engaging the drivingelement with the driven element, and means actuated by said means Jforengaging the rictional members with each other.

3. In a hydraulic clutch, a driving ele-v ment, a driven element, meansfor compressing fluid between thedriving and driven elements tooperatively engage them for movement in one direction, a pluralityroffriction elements, certain of the elements being engaged with thedriving element and certain others of the friction elements beingengaged With the driven element, and means operated by the iuidcompressing means for forcing the friction elements into frictionalengagement with each other to thereby engage the driving element withthe driven element.

4. in a hydraulic clutch, a driving element, a driven element, means foradmitting liuid between the driving and ldriven elements, means forcompressing the fluid in the space between the driving and drivenelements, moans for relieving the pressure of the iluid between thedriving and driven elements, a plurality of frictionally contactingelements normally held out of frictional engagement with each other, andsome of said elements being connected with the driving element and otherof said elements connected with the driven element, means actuated bythe compression of the iiuid between the driving and driven elementsforcing said ii-ictional elements into operative Contact with eachother.

ln a hydraulic clutclu'a driving element. a driven element, means foradmitting iiuid between the driving and driven elements. moans forcompressing Huid between said elements to thereby operatively engage theelements to each other for coincident movement, means for relieving thepressure of fluid between the driving and driven elements, a pluralityof friction disks, certain of the disks being operatively connected tothe driving element and certain other disks Being operatively connectedto the driven element, means actuated by the compression of fluidbetween the driving and driven elements acting to force said disks intofrictional engagement with each other, and means for relievingfrictional engagement between said disks when said compression isrelieved.

6. ln a hydraulic clutch, a driving element and a driven element, meansfor admitting fluid into the space between. the driving and drivenelements, means for compressing said fluid, a plurality of frictiondisks normally disengaged from each other, certain of the disks beingoperatively connected to 'the driven element and ccrtainother disksbeings;

operatively connected to the driving element;y

means for transmitting the pressure ofthe fluid compressed between thedriven and driving elements to said disks to cause'their frictionalengagement, means for relieving the pressure of lluid behind said disksto Q- 'thereby release frictional engagement between the disks, andmeans for relieving the conipressionof fluid between the driving anddriven elements.

7. In a hydraulic clutch, a driving elel, ment, a driven element, meansfor admitting Huid betweenl the driving and driven elements, means forcompressing Huid between the driving and driven elements to therebyoperatively e'ngage said elements for coincident movement, a pluralityof friction disks,

certain of the disks being connected to the driven elementand certain ofthe disks being connected to the driving element, ineans rcontrolled bythe pressure of fluid between the driving and driven elements forforcing said disks into frictional engagement with each other, a reliefvalve controlling discharge from the space between the driving and thedriven elements, and a valve controlling the transmission of pressurefrom'said space to said friction disks.

8. In a hydraulic clutch, a driving anda driven element, one of saidelements embodying a hollow casin and the other embodying K:rotordispose within the casing,

Ya pluraliy of friction disks mounted within the casing certain of thedisks being connected to the driving element and certain other disksbeing connected to the driven element, means for admitting a fluidmedium intoy the space between the rotor and outer casing, means carriedby the rotor for compressing said fluid medium between the rotor andcasing to thereby lock the driving and driven elements to eachother forcoincident movement, a relief valve controlling the discharge ofconpressed iuid medium from within said space, means for transmittingthe pressure of said fluid me- A 'dium when compressed to said frictiondisks to cause their frictional engagementl a valve controlling saidtransmission of pressure, and operative connections between the iirst-'named -valve and the last-named valve whereby the second-named valveshall operate successivelyl to the first-mentioned valve upon a movementof the first-named valve to prevent the discharge of fluid medium fromthe casing, and whereby the firstnamed valve shall operate successivelyto A the second-named valve upon the relief of Huid pressure behind saidfriction disks.

9. In a hydraulic clutch, a driving element and a driven element, oneembodying an 60 outer casing and the other fa rotor disposed vwithin thecasing, thelouter casing and the rotor hav-ing a common axis ofrotation, the inner face ofthe casing being 'cceiitric to the face ofthe rotor and touching the rotor 'l' l `at one point, saidrotor-beingformed with blade-"pockets and with passages communieating with thespace between the rotor and the casing and extending inward from a pointin advance of leach blade pocketY and' then outward to the outer face ofthe rotor,

shiftable blades mounted in the blade pockets, shiftable valves mountedinfsaid. passages, means for permitting the entrance of duid medium intothe space between the rotor and outer casing, and means `for shiftingsaid valves toA close or open the passages leading from the spacesdefined by lthe f A blades, the `rotor and the casing/ 7 l0. In ahydraulic clutchfa driving element and a driven element, one embodyingan outer casing and the other a rotor disposed within the casing, theouter casingl i and the iotor having a common axis of .rotation, theinner face of the casing'fb g eccentric to the face of the rotor and theA rotor touching thev saine at one point, said rotor being formed withbladepockets with passages communicating with the space between therotor and the casing and extending inward from a point in advance ,ofeach gI blade pocket and then outward to the outer face of the rotor,shiftable blades mounted in the blade pockets, shiftable tubular valvesopen at both ends and mounted :in said passages, means forpermitting'the entrancejp,

middle of the partition being open, said par-s tition dividing thecasing into two chambers, a rotor chamber and a fluid chamber, a rotor5' mounted within the rotor chamber andhavi ing a shaft projectingthrough the fluid chamber, the rotor and outer easing-having 11o acommonaxis of rotation but the inner face of the rotor chamber beingeccentric to said axis and the `rotor contacting at one point `with theinner face ef the chamber to there:

by form ailcompress1onspace on one ,side of 115 f said po'int ofcontactand an inlet space on the other side thereof, yielding blades mountedupon the rotor and contacting with the inner ace of the rotor chamber,valve controlled means for admitting fluid from 12e' the fiuid chamberixute the rotor chamber on the inlet side thereof, 'valve contiolled lmeans for relieving pressure between the rotor and the casing on thecompression side of the clutch, a plurality of friction disks mounted inthe fluid chamber and normally separated from each other, certain of the-.disks being `operatively connected to the outer casing and. certainothergdisks being operativelyv connected :togthe., rotor, valve 'madrescontrolled means for transmitting fluid' pressure from the space betweenthe rotor and the casing on the compression side of the clutch to saidfriction disks, ,means operatively connecting the several valves forcommon actuation, and shiftable means for actuating said valves.

l2. n a hydraulic clutch, an outer'casing constituting a driving elementand having a partition dividing the easing into two chambers, one ofthechambers constituting a rotor chamber and the other a fluid chamber, arotor in the rotor chamber, the rotor and casing having a common axis ofrotation but the interior face of the rotor chamber being eccentric tosaid axis, a plurality of radially yel'lable blades on the rotorengaging the face of the rotor chamber, said rotor being formed withdischarge ducts leading from the peripheral face thereof in advance ofeach of said'bladesI and communicating each with a duct disposedparallel to the axis of the rotor and opening upon the inner facethereof, tubular open-ended valves disposed in said lastnamed ducts andshiftable longitudinally therein to open or close the discharge ducts, asleeve mounted upon the rotor shaft and longitudinally shiftahlethereon,v said sleeve operatively engaging the tubular valves forshifting movement, and means for actuating said sleeve.

13. In a clutch, a driving and a driven element, a plurality of frictiondisks normally out of rictional engagement with each other, certain ofthe disks heilig operatively engaged with'the driving element-andcertain 'other disks being operatively engaged With the driven element,fluid compressing means operating to connect the driving and drivenelements, means for transmitting the fluid pressure to a plurality ofpoints behind said friction disks to cause their frictional engagement,and means for relieving said fluid pressure.

14. In a clutch, a driving' element, a driven element, a plurality offriction disks normally out of engagement with each other,'certain ofthe disks being operatively connected to the driving element and certainother disksbeing operatively connected to the driven element, pistonsdisposed behind said disks, means connected with the driving and drivenelements for exerting Huid piessure on said pistons to cause theengagementy of said disks, and means for relieving said fluid pressure.

15, A clutch including a driving element and a driven clement, spacedfrom each other, means'for introducing fluid between' the drivinganddriven elements, means carried by one of said elementsfor compressingsaid fluid, a )lurality of friction disks normally out oil engagementwith each other, certain of the friction disks being operativelyconnected to the driving element and certain other disks beingoperatively connected to the driven element, pistons dis posed behindsaid disks, means for establislif` c ing communication between thepistons and the space between the driving and driven elements, and meansfor disestablishing said communication andV relieving the viluid pres#sure behind said pistons.

16. In a clutch, a driving element anda driven element, one embodyinganouter casing and the. other a rotor, the outer casing l and the rotorhavin a common axis of rota;- tion but the inner ace of the outer casingbeing eccentric to the axis and touching the rotor at one point, theouter casing being formed with a plurality of piston cylinders l ductand open the second-named duct to the'v interior of the casing, meansfor compressing fluid between the rotorand the outer casing, and meansfor actuating saidvalve.

17. A hydraulic clutch including e: driving and driven element, oneembodying an outer casingand the other a rotor, the outer casing beingdivided by a partition into s {'luid chamber and a rotor chamber Withinwhich the rotor is located, the rotor chamber having its inner faceeccentric to the rotor and contacting therewith at one point, the

the face of the rotor chamber at one side of said point of contact,whereby a fluid medium may be admitted from the fluid chamber into therotor chamber, radially yieldable blades carried by -the rotor andengaging the face of the rotor chamber, and means carried by the rotorfor establishing or disestablishing communication between the spacesdefined by the casing, the rotor, and the blades and said Huid chamber.

18. A hydraulic clutch including a driving element comprising an' outercasing formed in two sections and an annular partition separating saidsections and formed with a marginal inlet port, said partition dividingrthe casing into a .rotor chamber and a fluid chamber, a rotor disposedin the rotor chamber and including a shaft passing through saidpartition and through the outer Wall of the fluid chamber, said rotorand casing having a common axis of rotation partition being formed`.vith an inlet port," opening into the space between the rotor and 1n.

ing eccentric to the rotor and touching it at one point, radiallymovable blades mounted 1on the rotor and contacting with the face. ofthe rotor chamber, the rotor being formed.

with a plurality oivducts set one in advance of each blade, said ductsextending inward 'andbeing there; annularly enlarged and.

communicating with ducts extending parsul() allel 'to theaxis of therotor, tubularA open- .endedvalves disposed in said last-named i ductsand adapted. to be shifted to close the discharge openings in thefirst-namedv ducts or open the same, a sliding sleeve lmounted upon therotor' shaft and having a ,head engaging said valves to. shift tie same,means for actuating said sleeve, an 'annular flange formed upon the faceof the partition and extending into the liuid chamber, cylinders formedupon the end wall of the fluid 'cham-,- ber, a plurality oi annularfriction disks bearingagainst the said partition and disposed within theannular flange, certain of the disks being operatively `connected tosaid flange and certain other disksbeing operatively connected to therotonr, a plurality of pistons for said cylinders and bearing at one endagainst said friction disks, a valve hhamber disposed in said fluidchamber and xaving on one side a. pair of ports and on the other side arelief port, the Wall of the outer"casing/`being providedy with a ductleading from the compression space of the rotor chamber to oneof saidpairs of ports and with a duct leading from the other of said pair ofports to said piston cylinders, a valve disposed within the Huid chamberand having passages adapted when the valve is /in one position toestablish communication between the first-named pair of orts and when inanother position to cut-o the duct leadinoV fromv the compression sideof the rotor hamber and establish communication between the relief portand the duct leading.

to the piston cylinders, and means carried by theshiftable sleeve on therotor shaftfor shifting said valve into the last-named position as thesleeve is shifted outward and 4

